“…Maciejewski (2012) proposed a control method for a single-degree-of-freedom seat with a simple pneumatic suspension. Ma and Chen (2011) developed a disturbance attenuation control of active suspension with nonlinear actuator dynamics, 1 Jiangsu Province Key Laboratory of Aerospace Power Systems, Nanjing University of Aeronautics and Astronautics, China 2 College of Engineering, Nanjing Agricultural University, China but the authors did not discuss the effect of uncertainties, which probably happens. For active suspension systems with hydraulic actuators, because of their strong nonlinear property, sliding-mode control (SMC), which is effective for nonlinear and parameter-uncertain systems (Utkin, 1977;Slotine and Li, 1991;Hung et al, 1993;Gao, 1998), has attracted the interest of many researchers recently (Choi and Han, 2007;Benelghali et al, 2011;Lian, 2013).…”